The overall objective is to gain better understanding of the memory systems and functions of the brain. This project is designed to clarify the mechanisms of temporary active memory in neuronal networks of the cerebral cortex. The question is important because active memory is essential for effective control of sequential behaviors and higher cognitive functions which are commonly deranged in certain mental disorders, notably schizophrenia. The proposed-research is basically computational and has two closely intertwined components: (a) the analysis of electrical discharge of cortical nerve cells in memory; and (b)the development of computer simulation models of cortical memory. Neuronal discharge will be recorded with multiple microelectrodes from parietal cortex of monkeys memorizing tactile stimuli. The role of recurrent activation of neurons in memory will be investigated by analysis of the patterns of spike discharge in single units and in multiple simultaneously recorded units. The role of prefrontal cortex in memory will be examined by studying the effects of cooling that cortex on parietal cells and on tactile memory performance. Resulting empirical models will be used as the source of empirically testable hypotheses of cortical network dynamics in active memory.